A simple Perl script to count the number of times
individual keys lines have been seen.

It's perl as I often use if on "bare bones" servers
where there's little installed to count eg the
number of different HTTP status codes returned as
seen in the log files:

    cat access.2011-08-24.log | \
      awk '{print $9}' | \
      distinct 
    distinct-keys, occurances
    200,107875
    500,459
    503,4790
    

The script is so simple that it's a doddle to 
make it fit your own needs.